平衡化降阶法及其在直升机增稳系统中的应用

本文介绍了平衡化降阶理论的思想、特点,并在此基础上研究加权平衡化降阶法。文章还就加权平衡化法在直升机控制中的应用给出了算例,成功地解决了对照国军标评判直升机增稳系统的飞行品质的问题。

Influence of joint spacing and rock characteristics on the toppling stability of cut rock slope through a simplified limit equilibrium method

Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a cutting slope occurred in a hydropower station in Kyushu,Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure.Thus,in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions,a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass.The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case,and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution,thus verifying the accuracy of the simplified method.Meanwhile,the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results.The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing,the joint frictional angle and the tensile strength of rock mass together.

Feasibility of flue-gas desulfurization by manganese oxides

For the purpose of effective and economic desulfurization of flue-gas, the predominance area diagram of the Mn-S-O system at different temperatures was constructed based on the thermodynamic data obtained from the literatures. It is seen from this figure that flue-gas desulfurization by manganese oxides is feasible from the thermodynamic point of view. Additionally, the most appropriate temperature range for flue-gas desulfurization is between 600 and 800 K, and the reaction is strongly exothermic to maintain the heat balance. The natural manganese ores encompass large tunnels that exhibit large surface areas and highly chemical activity, which can provide a high enough SO2 removing efficiency. From the superposition of the diagrams of Mn-S-O and Fe-S-O systems, it is found that there is a coexistent stability region of MnSO4 and Fe2O3, which provides the possibility of desulfurization by selective sulfation without ferric sulfate forming. A multi-stage desulfurization system has been discussed briefly.

RESEARCH ON MATRIX CRACK EVOLUTION OF CROSS-PLY CERAMIC MATRIX COMPOSITE

The matrix crack evolution of cross-ply ceramic matrix composites under uniaxial tensile loading is investigated using the energy balance method.Under tensile loading,the cross-ply ceramic matrix composites have five damage modes.The cracking mode 3 contains transverse cracking,matrix cracking and fiber/matrix interface debonding.The cracking mode 5 only contains matrix cracking and fiber/matrix interface debonding.The cracking stress of modes 3 and 5 appearing between existing transverse cracks is determined.And the multiple matrix crack evolution of mode 3 is determined.The effects of ply thickness,fiber volume fraction,interface shear stress and interface debonding energy on the cracking stress and matrix crack evolution are analyzed.Results indicate that the cracking mode 3 is more likely to appear between transverse cracks for the SiC/CAS material.

Progress in the Study on the Phase Equilibria of the CO2·H2O and CO2-HeO-NaCI Systems

To study the feasibility of CO2 geological sequestration,it is needed to understand the complicated mul- tiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological condi- tions(273.15—473.15K,0—60MPa),which are also essential for designing separation equipments in chemical or oil-related industries.For this purpose,studies on the relevant phase equilibria and densities are reviewed and ana- lyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable pre- dictions in a wide temperature and pressure range.Besides,three different models(the electrolyte non random two-liquid(ELECNRTL),the electrolyte NRTL combining with Helgeson model(ENRTL-HG),Pitzer activity co- efficient model combining with Helgeson model(PITZ-HG))are used to calculate the vapor-liquid phase equilib- rium of CO2-H2O and CO2-H2O-NaCl systems.For CO2-H2O system,the calculation results agree with the experi- mental data very well at low and medium pressure(0—20MPa),but there are great discrepancies above 20MPa.For the water content at 473.15K,the calculated results agree with the experimental data quite well.For the CO2-H2O-NaCl system,the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52mol·L -1 .Bur for the NaCl concentration of 3.997mol·L -1 ,using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model.It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers.More experimental data and more accu- rate thermodynamic calculations are needed in high temperature and pressure ranges(above 398.15K and 31.5MPa).

Measurements of Hydrate Equilibrium Conditions for CH4, CO2, and CH4＋C2H6＋C3H8 in Various Systems by Step-heating Method

Phase equilibrium conditions of gas hydrate in several systems were measured by the step-heating method using the cylindrical transparent sapphire cell device.The experimental data for pure CH4 or CO2+deionized water systems showed good agreement with those in the literatures.This kind of method was then applied to CH4/CO2+sodium dodecyl sulfate(SDS)aqueous solution,CH4/CO2+SDS aqueous solution+silica sand,and(CH4+C2H6+C3H8)gas mixture+SDS aqueous solution systems,where SDS was added to increase the hydrate formation rate without evident influence on the equilibrium conditions.The feasibility and reliability of the step-heating method,especially for porous media systems and gas mixtures systems were determined.The experimental data for CO2+silica sand data shows that the equilibrium pressure will change significantly when the particle size of silica sand is less than 96μm.The formation equilibrium pressure was also measured by the reformation of hydrate.

Thermodynamic equilibrium of bismuth hydrometallurgyin chloride and nitrate solutions

Simultaneous equilibrium was applied to the thermodynamic analysis and calculation of Bi（Ⅲ）-X（Cl-, NO-3）-H2O systems, based on which the diagrams of the logarithm of equilibrium concentration of Bi（Ⅲ） of series precipitation vs pH value of these two systems at 25 ℃ were obtained, and the pH ranges of the stable zones of various precipitations were analyzed and determined. In Bi（Ⅲ）-Cl--H2O system, the variations of c0(Bi3+) and （c0（Cl-）） have little effect on the equilibria of Bi（OH）3-solution and BiOOH-solution, but has great influence on the （equilibrium） of BiOCl-solution. However, in Bi（Ⅲ）-NO-3-H2O system, the variations of c0(Bi3+) and c0（NO-3） have little effect on equilibria of Bi（OH）3-solution, BiOOH-solution and Bi2O3-solution. When pH value is high, Bi2O3 is the thermodynamic stable phase, its stable zone is the widest, almost including the stable zones of BiOCl or （BiONO3,） （Bi（OH）3） and BiOOH. Bi（OH）3 cannot be obtained from Bi（Ⅲ）-Cl--H2O system, even strong alkaline media. Bi2O3 can be obtained from the solution directly, and highly pure BiOCl or BiONO3 can also be obtained through strictly controlling pH value.

Optimization of assembly line balancing using genetic algorithm

In a manufacturing industry, mixed model assembly line(MMAL) is preferred in order to meet the variety in product demand. MMAL balancing helps in assembling products with similar characteristics in a random fashion. The objective of this work aims in reducing the number of workstations, work load index between stations and within each station. As manual contribution of workers in final assembly line is more, ergonomics is taken as an additional objective function. Ergonomic risk level of a workstation is evaluated using a parameter called accumulated risk posture(ARP), which is calculated using rapid upper limb assessment(RULA) check sheet. This work is based on the case study of an MMAL problem in Rane(Madras) Ltd.(India), in which a problem based genetic algorithm(GA) has been proposed to minimize the mentioned objectives. The working of the genetic operators such as selection, crossover and mutation has been modified with respect to the addressed MMAL problem. The results show that there is a significant impact over productivity and the process time of the final assembled product, i.e., the rate of production is increased by 39.5% and the assembly time for one particular model is reduced to 13 min from existing 18 min. Also, the space required using the proposed assembly line is only 200 m2 against existing 350 m2. Further, the algorithm helps in reducing workers fatigue(i.e., ergonomic friendly).

Stability and Influence Factors Analysis of Wharf Slope on Slippery Stratum

With the growing tension of port shoreline resource in Three Gorges Reservoir area, many wharfs can only be constructed on slippery stratum with poor geological condition, which means buckling failure occurs easily. FEM strength reduction method is used in analyzing slope stability of a wharf in Chongqing, and its accuracy is verified by comparing the acquired results with the computation of traditional limit equilibrium method. On this basis, the influences of reservoir water level variation, overload and backfill material behind the retaining wall, and soil share strength of wharf slope on slippery stratum are analyzed. Analysis shows that, there＇ s a most adverse water level in wharf slope, and the engineering proposals with a certain practical significance such as improve the drainage behind retaining wall, controll overload and improve the strength of backfill soil and subsoil are suggested.

A Modified Homogeneous Balance Method and Its Applications

A modified homogeneous balance method is proposed by improving some key steps in the homogeneousbalance method.Bilinear equations of some nonlinear evolution equations are derived by using the modified homogeneousbalance method.Generalized Boussinesq equation,KP equation,and mKdV equation are chosen as examples to illustrateour method.This approach is also applicable to a large variety of nonlinear evolution equations.

A Model-based Phenomenological Investigation of Char Combustion Kinetics through Thermogravimetry

Five coal char samples were burnt in thermobalance with ramp heating rate of 30 K/min. The pore structure of these char samples was studied through mercury intrusion method. Combined with the kinetic theory of gases, the data of surface area was used in fitting the results. As a result, the kinetic triplet was given. The analysis showed that five char samples share almost the same intrinsic activation energy of the overall reaction. The phenomenological implication of the derived combustion rate equation was given.

A Routing Optimization Algorithm with Quality of Multi- Service in Wireless Sensor Network

According to the problem of energy consumption in wireless sensor network （WSN）,this paper puts forward a routing optimization algorithm with quality of multi-service, using the function of routing optimization with quality of multi-service and membership function of satisfaction, which integrates the energy consumption of communication and residual and the information of time delay into the membership function of satisfaction to solve the equilibrium factor, so that it can become the optimal routing that balances the network lifetime, transmission delay of data, and node energy consumption of nodes. Simulation experiment shows that adopting the algorithm can make lifecycle of nodes longer and network transmit more data packets at the same time. Experimental results verify the algorithm can effectively balance the network energy, reduce the energy consumption and prolong the network lifetime.

Infrared spectroscopic study on chemical and phase equilibrium in triethylammonium acetate

Protic ionic liquid (PIL) triethylammonium acetate was prepared by mixing equimolar amounts of acetic acid and triethylamine, and then studied using the combination of the Attenuated Total Reflection Fourier Transform Infrared spectroscopy, in-situ infrared spectroscopy, pH, and conductivity titration measurements. It was found that the equimolar synthesized triethylammonium acetate was separated into two layers, which suggesting that there were both chemical and phase equilibrium in this solution. Molecular species could be directly observed in the IR spectra over the range of 1200-1800 cm-1 and also checked by 1H NMR. Based on analysis, the upper layer was rich in amine with little acid and PIL, and the down layer was rich in PIL with residual acetic acid and amine. And single PIL-rich layer could be separated into two layers again when the mole ratio of newly added triethyamine to the theoretical produced triethylammonium acetate reached 0.12.

Optimized algorithm for balancing clusters in wireless sensor networks

Wireless sensor networks consist of hundreds or thousands of sensor nodes that involve numerous restrictions in-cluding computation capability and battery capacity.Topology control is an important issue for achieving a balanced placement of sensor nodes.The clustering scheme is a widely known and efficient means of topology control for transmitting information to the base station in two hops.The automatic routing scheme of the self-organizing technique is another critical element of wireless sensor networks.In this paper we propose an optimal algorithm with cluster balance taken into consideration,and compare it with three well known and widely used approaches,i.e.,LEACH,MEER,and VAP-E,in performance evaluation.Experimental results show that the proposed approach increases the overall network lifetime,indicating that the amount of energy required for com-munication to the base station will be reduced for locating an optimal cluster.

Multi-parameter Tikhonov Regularization—An Augmented Approach

We study multi-parameter regularization(multiple penalties) for solving linear inverse problems to promote simultaneously distinct features of the sought-for objects. We revisit a balancing principle for choosing regularization parameters from the viewpoint of augmented Tikhonov regularization, and derive a new parameter choice strategy called the balanced discrepancy principle. A priori and a posteriori error estimates are provided to theoretically justify the principles, and numerical algorithms for efficiently implementing the principles are also provided. Numerical results on deblurring are presented to illustrate the feasibility of the balanced discrepancy principle.

A GENERAL ITERATIVE METHOD OF FIXED POINTS FOR EQUILIBRIUM PROBLEMS AND OPTIMIZATION PROBLEMS

The purpose of this paper is to present a general iterative scheme as below：{F（un,y）＋1/rn（y-un,un-xn）≥0,y∈C,xn＋1=（I-αnA）Sun＋αnγf（xn）and to prove that, if {an} and {rn} satisfy appropriate conditions, then iteration sequences {xn} and {un} converge strongly to a common element of the set of solutions of an equilibrium problem and the set of fixed points of a nonexpansive mapping and the set of solution of a variational inequality, too. Furthermore, by using the above result, we can also obtain an iterative algorithm for solution of an optimization problem min h（x）, where h（x） is a convex and lower semicontinuous functional defined on a closed convex subset C of a Hilbert space H. The results presented in this paper extend, generalize and improve the results of Combettes and Hirstoaga, Wittmann, S.Takahashi, Giuseppe Marino, Hong-Kun Xu, and some others.